A better understanding of what causes grain raising will help you manage it.
By Bob Flexner
Grain raising, including its causes and how to handle it, is not well understood by woodworkers. This leads to instructions that result in your sanding more than necessary to remove it and often not making the problem better. Understanding what’s happening in the wood will help you improve your work. First, some definitions.
To begin with, the very term “grain raising” is a little misleading. When we speak of grain in wood, we usually mean the visible boundaries between the tree rings. So, for example, with plain-sawn oak the boundaries are wide and clearly visible.
To understand the grain raising that creates fuzz on the wood you need to take a different perspective of grain. The grain that’s being referred to here is the tiny cells or fibers that makeup the wood. These cells are way too small to be visible except under magnification. So to make this explanation clearer, think of them as a bundle of miniature soda straws.
Like the soda straws, the cells in wood are largely hollow and much longer than they are thick. In wood the cells are held together by a “glue” called lignin, which also contains the extractives that give wood its color.
When you saw or plane the end grain of wood, you have to use very sharp blades or the sides of the cells tear and collapse.
Purchase the June 2018 issue of Popular Woodworking here.